1. Technical Field
The present invention relates to a correction information calculating device, an image processing apparatus, an image display system, and an image correcting method.
2. Related Art
Generally, as one example of an image display device, a projector is known. Projectors have advantages such as ease of installation and the ability to display a big screen image. Recently, image display systems displaying an image by using a plurality of projectors have been proposed. These image display systems display one image by composing a plurality of partial images by allowing a plurality of projectors to project the partial images.
In order to correct distortion of a partial image or a difference in the relative positions of partial images, for example, the following process is performed. First, a measurement pattern including characteristic points are displayed, and the displayed measurement pattern is photographed. Then, correction information representing the amount of correction of the positions of pixels is acquired based on the correspondence relationship between the position of a characteristic point on image data representing the measurement pattern and the position of the characteristic point in the photographed image acquired for each projector by photographing the measurement pattern. In a case where an image (hereinafter, referred to as a content image) for a viewer is displayed, image data representing the image is corrected based on the above-described correction information, and partial images are displayed based on the corrected image data.
In order to perform the above-described correction process, the correspondence information between the measurement pattern on a projection surface and a projector that projects the measurement pattern needs to be acquired (for example, see JP-A-2009-086485). In JP-A-2009-086485, identification images including different identification information for a plurality of projectors are projected from the projectors. Then, correspondence matching between the projectors and projected areas projected by the projectors is performed based on the identification images included in photographed images acquired by photographing the projected identification images.
In the technology disclosed in JP-A-2009-086485, since identification patterns corresponding to the number of used projectors are necessary, the number of projectors that can be used is limited to the number of the identification patterns prepared in advance. In addition, in order to increase the number of the identification patterns, the identification patterns become complicated shapes. In a case where the identification patterns have complicated shapes, there is a concern that a process for detecting the identification pattern from a photographed image may be complicated or the robustness of the process may be degraded due to a detection failure or the like.